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Peter Mantas Ottawa Lawyer

Peter N. Mantas

Partner Fasken
In an increasingly complex business world, the risk of running afoul of the law, both at home and abroad, cannot be underestimated.
Jurisdiction Ontario, 1994 | New York, 1993
Office(s) Ottawa, London


Peter Mantas is a senior litigation partner frequently retained to act in complicated, high stakes matters of national and international importance. Clients appreciate Peter’s experience, strategic advice, knowledge, and tough but reasonable approach. He is also valued for his skills in crisis management, reputational risk and public relations.

Peter has significant experience as counsel in all aspects of the litigation process, with particular expertise in international and domestic arbitrations. He is sought after for his knowledge in disputes involving government, mining, trade, procurement and technology.

Peter leads Fasken’s Ottawa litigation team, the firm’s Procurement group, and co-leads its White Collar Defence and Investigations group.

Peter has been repeatedly recognized by Legal 500, Benchmark Litigation, Who’s Who Legal, Chambers and Best Lawyers in Canada. Peter has been nominated in Canadian Lawyer magazine as one of the 25 most influential lawyers in Canada.

Peter has acted as counsel in the following notable matters:

  • Largest litigation settlement in Canadian history ($23 billion), and one of the largest in world history, on behalf of the Assembly of First Nations and others involving the federal government’s role in the forced removal of Indigenous children from their families and the systemic discrimination against these children.
  • Successful challenge of major procurement decision by Ontario government for breaching Canada’s free trade agreement with Europe (CETA). Case named one of the top ten business decisions of 2022 in Canada by Lexpert magazine.
  • Investor state dispute on behalf of Australian investors arising under the Australian-India Bilateral Investment Treaty (BIT) in relation to the expropriation of India’s Bhukia gold mine project.
  • Leader of Fasken team appointed to the international trade dispute panel for the United Kingdom government.
  • Counsel to the Courts Administration Service for the Federal Court, Tax Court and Court Martial Appeals Court of Canada, to maintain unimpeded access to the courts during a national labour strike by federal public servants.
  • Arbitration before the International Commercial Court (ICC), under English law and with the seat of arbitration in London, in relation to a contractual and procurement dispute at one of the largest cobalt and copper mines in the world, located in the Democratic Republic of Congo.
  • Arbitration before the International Commercial Court (ICC), under French law and with the seat of arbitration in Paris, in relation to a shareholder dispute at one of the largest lithium mining projects in the world, located in the Democratic Republic of Congo.
  • Cross border multi-jurisdictional dispute before the courts of Ontario and New York, on behalf of Export Development Canada (EDC), with regards to a commercial and financing matter involving Amtrak and the Phillip Morris Corporation.
  • Defence of decision by the Conservative Party of Canada to disqualify a candidate from the party leadership race for posting racist comments on social media.
  • Counsel to Thales in relation to a public inquiry into Ottawa’s light rail system.
  • Arbitration before Canadian panel involving multijurisdictional (Canada-USA) cryptocurrency dispute.
  • Arbitration on behalf of Rogers Communications involving traffic pumping and findings by the CRTC.
  • Action against the federal government on behalf of US company to challenge an award of the largest procurement in Canadian history (over $60 billion) in relation to the replacement of Canada’s naval frigates and destroyers.
  • Counsel to Cabinet Minister and President of the Treasury Board Scott Brison in relation to the leak of Cabinet secrets in the R. v. Admiral Mark Norman case.
  • Action on behalf of Rogers, Bell and Quebecor with respect to the collection of ringtone royalties by SOCAN.
  • Action for Ethnic Channels Group (ECG) in an international broadcasting rights and contract dispute between ECG USA and Moscow based CTC Media.
  • Defence counsel to TPG Consulting in an 8-month criminal jury trial for alleged bid rigging and fraud in relation to IT services to the federal government. TPG, its executives and consultants were all acquitted.
  • Action by Odyssey TV regarding Internet and broadcasting piracy by Ellas TV. Case resulted in one of the largest monetary awards for breach of copyright in Canadian history.
  • Counsel to Rockstar Consortium (Apple, Blackberry, Ericsson, Microsoft and Sony) regarding depositions conducted in relation to the global Nortel pension bankruptcy litigation.
  • Counsel to the New Democratic Party of Canada in relation to delayed filings by multiple candidates for federal election.
  • Counsel to former Chief of Staff to the Prime Minister, Nigel Wright, in the case of R. v. Senator Duffy.
  • Counsel to the Prime Minister of Canada and others with respect to the removal of former Cabinet Minister Helena Guergis from her position in Cabinet and caucus.


Client Work

  • Thales DIS Canada Inc. disputes procurement decision under the Comprehensive Economic and Trade Agreement and the Canadian Free Trade Agreement, Ongoing since January 2022
  • Thales Canada Inc. disputes refusal of proposal related to a federal procurement with the Canadian International Trade Tribunal, Ongoing since January 2022
  • Panthera Resources PLC retains Fasken in its dispute under the Australia-India Bilateral Investment Treaty, against the Republic of India, Ongoing since March 2021
  • Parker Johnston Industries Ltd. among first organizations to successfully challenge several public procurements issued under the CFTA, Ongoing since February 2020
  • Assembly of First Nations obtains C$20 billion settlement, largest litigation settlement in Canadian history, Ongoing since March 2019
  • Alion Science and Technology Corporation challenges decision in C$60 billion public procurement—the largest in Canadian history, Ongoing since November 2018
  • Music Choice vs. Stingray Digital Group Inc. and Nextologies Limited, Ongoing since September 2018
  • Odyssey et al v. Ellas TV et al, 2018 FC 337,
  • iA Financial Group acquires PPI Management and its subsidiaries,

Career & Education


  • LLB University of Ottawa
  • BA, Trinity College University of Toronto

Community involvement

  • Member of the Advisory Committee to the Canadian International Trade Tribunal (CITT)


Fasken Institute



Article Commentary: Anti-corruption rules watered down for US miners The Northern Miner
Article President Trump and Congress Water Down Anti-Corruption Rules for U.S. Mining Companies White Collar Post
Article CASL 2017: The Sleeping Giant Awakens Capital Perspectives

Speaking Engagements

Program Faculty Domestic and Foreign Legal Exposure to Alleged Violations of International Human Rights OsgoodePD
Speaker Government Procurement in the EU CETA Business Summit location location Ottawa, ON


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